diff --git a/lib/banzai/filter/sanitization_filter.rb b/lib/banzai/filter/sanitization_filter.rb
index 6e13282d5f4..ca80aac5a08 100644
--- a/lib/banzai/filter/sanitization_filter.rb
+++ b/lib/banzai/filter/sanitization_filter.rb
@@ -7,7 +7,7 @@ module Banzai
       UNSAFE_PROTOCOLS = %w(data javascript vbscript).freeze
 
       def whitelist
-        whitelist = super.dup
+        whitelist = super
 
         customize_whitelist(whitelist)
 
@@ -42,8 +42,6 @@ module Banzai
         # Allow any protocol in `a` elements...
         whitelist[:protocols].delete('a')
 
-        whitelist[:transformers] = whitelist[:transformers].dup
-
         # ...but then remove links with unsafe protocols
         whitelist[:transformers].push(remove_unsafe_links)